Once in a small town lived an old blind man. He was blind yet while walking out at night he used to carry lighted lamp with him. One night while he was out of his house, a group of young travelers saw him. After seeing him they realized that he was blind. Travelers couldn't understand why would a blind person carry a lighted lamp and started making fun of him. One to those travelers got curious and asked, "You are blind and can't see anything then why do you carry lighted lamp with you??"Blind man replied, "Yes.. I am blind and can't see anything still I carry a lighted lamp with me for people like you.. who can see.if I walk at night without lamp, one may not be able to understand that a blind man is coming and could end up pushing me.."They felt ashamed for their behavior and apologized. 
We should respect differences also as everything has it's own importance in this world. 